244 CEYLON PEARL OYSTER REPORT. 



PLATE VII. (All the figures from photographs.) 



Fig. 1. Siphonochalina communis, var. tenuispiculata ; R.N. 117, reduced to nearly ^. 



,, 2. Ceraochalina multiformis, var. mtmaarensis ; R.N. 98, x about i. 

 3. ,, ceylonica ; R.N. 5, x about i. 



4. Pachychalim spinilamella ; R.N. 94, x about i. 



5. Gelliodes carnosa ; R.N. 69, x about -J. 



C. Colhcalypta digitata ; R.N. 74a, nearly natural size. 



PLATE VIII. (All the figures from photographs.) 



Fig. 1. Plocamia mcmaarensis ; R.N. 107, x about |. 



2. Clathria spiadosa, var. tessellata ; R.N. 92, x about f. 



3. PhaJcellia ceylonensis ; R.N. 34, x Jj;. 



,, 4. Acarnus ternatus ; R.N. 105, x about J. 



,, 5. Baspailia frutieosa, var. tenuiramosa; E.N. 100, x about i. 



,, G. Acanthella carteri ; R.N. 36, x about . 



PLATE IX. 



Fig. 1. Strongylophora duiissima ; R.N. 244. Part of dermal skeleton, x 230. 



/., microxea; s., strongyla. 

 ,, 2. Toowchalina robusta, var. ridleyi ; R.N. 109. Part of main skeleton in vertical section, x 230. 



o., oxea ; t., toxa. 

 3. Gelliodes petrosioides ; R.N. 146. Spicules, x 230. a., b., c, megascleres ; d., sigmata. 

 ,, 4. Desmacella tubulata ; R.N. 324. Spicules, x 230. 



a., b., styli ; c, sigmata ; /!., trichodragmata j e., isolated microxeote. 

 ,, 5. Acantlumfer ceylonensis ; R.N. 247. Spicules, x 230. 



., smooth oxeote ; /'., stylus ; c, spined oxeote ; d., trichodragmata. 

 ,, G. Gelliodes incrustans ; R.N. 112. Part of dermal skeleton, x 230. o., oxea ; s., sigmata. 

 ,, 7. Gellius cmgulatus, var. ccmaliculata ; R.N. 140. Spicules, x 230. 



a., oxeote ; /'., sigmata ; r., toxiform. 

 8. Eeniera zoologica ; R.N. 262. Oxea, x 360. 

 ,, 9. Petrosia densissima ; R.N. 138a. Oxea, x 3G0. 

 10. Reniera jrigmentifera ; R.N. 290. Spicules, x 360. ., oxeote; />., strongylote ; c, d., stylote. 



PLATE X. 



Fig. 1. Pachychalina subeylindrica ; R.N. 292. Part of dermal skeleton, x 52. 

 2. R.N. 292. Oxea, x 360. 



,, 3. Chalina clathrata ; R.N. 102. Part of skeleton in tangential section near the surface, x 360. 

 ,, 4. ( 'eraodwiina retiarmata ; R.N. 342. Oxea, x 360. 



,, 5. Chalina subarmigera; R.N. 116, about half natural size (dry specimen, from photograph). 

 6. Ceraochalina ceylonica ; R.N. 50. Oxea, x 360. 

 ,, 7. Pachychalina brevispiculifera ; R.N. 110. Oxea, x 360. 

 8. Ceraochalina retieutis ; R.N. 58. Part of dermal skeleton, x 360. 



a., well developed oxea, lying for the most part outside the horny fibre; v.s., vestigial oxea, 

 lying in the horny fibre. 

 !). Cludina obtusispmdifera ; R.N. 370. Part of surface skeleton, x 360, 

 10. Trachyopsis halicJwndrioides : R.N. 147. Oxea, x 230, 



